Surgical operations to remove the distal colon and part of the rectum are common for illnesses such as neoplasia, diverticular disease and inflammatory bowel disease. When the continuity of the intestinal tract is to be preserved, the bowel must be reconnected, for example, by means of sutures, staples or a compression device. This connection is called an anastomosis.
If there is a defect in the anastomosis, bowel content can leak out of the bowel and contaminate the normally sterile peritoneal cavity, causing peritonitis. Peritonitis (infection of the peritoneal cavity) can be lethal, and, therefore, measures must be taken during surgery to ensure that defects in the anastomosis are not present. One such measure is to fill the pelvic portion of the abdominal cavity with saline or water to a level that immerses the completed anastomosis, then insufflate the rectum with air while occluding the bowel above the anastomosis. As the rectum distends, the pool of saline is observed for air bubbles that, if present, signal a defect in the anastomosis, i.e., a leak, which must then be repaired.
One method currently used to insufflate the rectum is to insert a catheter into the rectum and, through the catheter, inject air into the rectum with a large syringe. The catheter may or may not have an inflatable retention cuff at its tip. A Foley catheter is a useful example of a catheter with an inflatable cuff that is readily available in an operating room. In this method, air is injected into the rectum through the catheter, the catheter is then clamped or crimped, the syringe is detached, refilled with air, reattached to the catheter, and more air is injected. This cycle is continued until the rectum is sufficiently distended with air. This method utilizes both a catheter and a syringe and is somewhat cumbersome.
A more frequently used device to insufflate air into the rectum and distend an anastomosis is a proctoscope, i.e., a rigid cylindrical instrument designed for looking into the rectum. A proctoscope, also referred to as a sigmoidoscope, is a type of endoscope. The proctoscope has a tubing port to which tubing from an insufflation bulb is attached. With the lens gate of the proctoscope closed, air is introduced into the rectum by compressing the insufflation bulb. Less frequently, flexible endoscopes, e.g. flexible sigmoidoscopes or colonoscopes, are used to inflate and inspect the anastomosis. Flexible endoscopes also have channels for air insufflation.
Use of a proctoscope for rectal insufflation to test for anastomotic leaks has advantages and disadvantages. The fact that proctoscopes are items usually stocked in an operating room is an advantage. Thus, an additional surgical instrument does not need be purchased or stocked in an operating room in order to test for anastomotic leaks. Moreover, it is advantageous that it is possible to visually inspect the anastomosis from inside the bowel using the proctoscope. This helps identify potentially harmful bleeding, which can then be stopped by suture ligation.
On the other hand, a significant disadvantage of the use of a proctoscope results from the fact that a sterile proctoscope has to be contaminated to check for leaks and then repackaged and sterilized for future use. The cost savings gained by using an instrument already in stock and accessible may be lost by the extra labor involved in cleansing, repackaging and sterilizing the instrument after surgery.
Another disadvantage is that if a proctoscope is used at the very start of surgery to examine a rectal tumor or cleanse the rectum, as is often done, then it must either be kept in the operating room in a dirty state, or cleansed in a nearby utility room by a nurse, until such time as it is again needed to test the anastomosis. This not only clutters the operating room, but can potentially contaminate the operating room, and in any event, necessitates extra labor, for example, by a circulating nurse.
An additional disadvantage of using a proctoscope to insufflate the rectum is that the insufflated air tends to leak out through the anus around the proctoscope, which typically has an outer diameter of about 0.75 inches. It therefore requires some extra effort to distend the rectum to the desired amount to effectively test the anastomosis. This problem is accentuated when the anastomosis is at or near the anus. When the anastomosis is very low, it may be impossible to inflate the anastomosis to the desired pressure.
Another disadvantage of using a proctoscope or other endoscope, or catheter, is that these instruments do not provide a mechanism to signal the surgeon when a specified air pressure is reached, and thus the air pressure can only be grossly evaluated by visual inspection of the distended bowel above the pool of saline, or by feeling the bowel. An anastomosis my therefore be under-inflated, in which case an anastomotic defect might go unrecognized.
Another disadvantage of using a proctoscope or other endoscope, or catheter, is that these instruments do not provide a mechanism to prevent overinflation, which may possibly damage or disrupt an anastomosis.
Furthermore, before performing an anastomosis some surgeons prefer to cleanse the bowel with an antiseptic. If a proctoscope that was used earlier to view a tumor or cleanse the rectum is reused to test an anastomosis without being resterilized, then the rectum will be insufflated with particles of fecal debris or airborne bacteria that remain within the scope or within the insufflation bulb or tubing that carries air from the insufflation bulb to the proctoscope. Such fecal debris or airborne bacteria could contribute to the development of postoperative peritonitis or wound infection when forced through an anastomotic defect into the sterile peritoneal cavity.
Thus, there are significant drawbacks to the use of a standard proctoscope to insufflate air into the rectum and to inspect an anastomosis and it would be desirable to provide alternative means to insufflate the rectum and inspect the anastomosis that avoid these drawbacks.
Operations of the upper intestinal tract also may require the formation of an anastomosis. For example, “gastric bypass” is a commonly performed operation on the morbidly obese that has been shown to produce significant weight loss. In this operation, a gastroenteric anastomosis is formed between a portion of the stomach and the small bowel. Bariatric surgeons often test their gastric anastomoses by a method similar to that described above for a colorectal anastomosis. Thus, they insufflate air or a gas into the stomach by means of a tube passed through the mouth into the stomach (a gastric tube). They occlude the bowel beyond the anastomosis and immerse the anastomosis in clear fluid. If they see air bubbling out of the bowel, through the fluid, they know that they have a defective anastomosis and must repair it immediately.
The most common way the stomach is insufflated during surgery is by passing a gastroscope into the esophagus or stomach. A gastroscope is another type of flexible endoscope. Gastroscopes are routinely used for examining the stomach and are attached to air pumps that insufflate the organ through a channel in the scope. However, this requires the availability and preparation of the gastroscope, and also requires the surgeon to remove the gastric calibration tube often used in bariatric surgery. Another method is to inflate the anastomosis with gas (e.g., oxygen) by attaching an infusion line from the anesthesiologist's cart to the gastric calibration tube. Either method is somewhat cumbersome, and neither allows the surgeon to inflate to a standardized pressure, or to measure, determine or record the precise inflation pressure.